Descripción
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We studied the effects of commercial humic substances derived from leonardite at different rates (0, 0.25, 2, 10 g kg?1) and pH (4.5, 6.0, 8.0) on Cu and Zn mobility, to evaluate their use for remediation of metal contaminated mine soils and to optimize their application conditions. We conducted a single-step extraction experiment and analyzed extracts for metal concentrations, soluble organic carbon and their E4/E6 ratio (ratio of absorption at 465 to 665 nm). Metal speciation in a soil solution was simulated by NICA-Donnan. Increasing the amount of humic substances and the pH caused higher release rates of soluble organic carbon with a lower humic/fulvic acids ratio. This led to a higher mobility of metals (up to 110 times Cu concentration in control and 12 times for Zn) due to the formation of soluble metal-humic complexes. Speciation modeling predicted that increasing rates of humic substances would result in a higher proportion of Cu and Zn associated with fulvic acids, more mobile than the humic acids fraction. Application of commercial leonardite humic substances at 2?10 g kg?1 and with pH levels similar to or below natural soil could be useful for assisted-phytoextraction of contaminated anthropogenic soils. High rates of humic substances in more alkaline conditions could entail a considerable risk of metal leaching to groundwater, toxicity and transfer to the trophic chain. | |
Internacional
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JCR del ISI
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Si |
Título de la revista
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Sustainability |
ISSN
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2071-1050 |
Factor de impacto JCR
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2,592 |
Información de impacto
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Datos JCR del año 2018 105/250 environmental Sciences |
Volumen
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11 |
DOI
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10.3390/su11184844 |
Número de revista
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19 |
Desde la página
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4844-1 |
Hasta la página
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4844-13 |
Mes
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OCTUBRE |
Ranking
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